Deployable reflector assembly

ABSTRACT

A deployable reflector assembly for electromagnetic radiation having a deployable circular T-shaped reflector ring structure attached to and surrounding a deployable reflector. The deployable circular T-shaped reflector ring has hinged folding panels, rotatable panels rotatably connected to the folding panels and wedge-shaped members that are hinged to the rotatable panels. Upon deployment, the hinged folding panels form a substantially cylindrical ring and the wedge-shaped members and rotatable panels form a substantially flat disk that is perpendicular to the central axis of the cylinder that is formed by the fully deployed folding members. The resulting deployed circular reflector ring structure has a rigid T-shaped section. As the circular reflector ring structure is deployed, it pulls the reflector into its operational configuration. Means such as a wire connected to an electric motor or torsion springs are provided for deploying the reflector.

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States Patent [54] DEPLOYABLE REFLECTOR ASSEMBLY 10 Claims, 6 Drawing Figs.

[52] 11.5. C1 350/299, 343/915, 350/288 [51] lint. Cl. G02b 5/08 [50] Field 01 Search 350/288,

[56] References Cited UNITED STATES PATENTS 2,430,915 7/1946 Evans 350/295 Primary Examiner-David Schonberg Assistant ExaminerMichael .1. Tokar Attorney-Michael W. York ABSTRACT: A deployable reflector assembly for electromagnetic radiation having a deployable circular T-shaped reflector ring structure attached to and surrounding a deployable reflector, The deployable circular T-shaped reflector ring has hinged folding panels, rotatable panels rotatably connected to the folding panels and wedge-shaped members that are hinged to the rotatable panels. Upon deployment, the hinged folding panels form a substantially cylindrical ring and the wedgeshaped members and rotatable panels form a substantially flat disk that is perpendicular to the central axis of the cylinder that is formed by the fully deployed folding members. The resulting deployed circular reflector ring structure has a rigid T-shaped section. As the circular reflector ring structure is deployed, it pulls the reflector into its operational configura tion. Means such as a wire connected to an electric motor or torsion springs are provided for deploying the reflector.

IDIEIPILOYABLIE REFLECTOR ASSEMMILY This invention relates to a deployable reflector assembly for electromagnetic radiation and more particularly to a deployable reflector assembly having a deployable T-shaped reflector ring structure that is attached to and surrounds a deployable reflector.

A deployable reflector for reflecting electromagnetic radiation has many uses and is particularly suitable for use in space since it can-be launched in a collapsed condition and then deployed when in the desired location in space. However, for use in space a satisfactory deployable reflector must be capable of being folded into a compact size so that it will fit easily into the launch vehicle that will place it in space and then it must be capable of presenting a large reflective surface when it is in the deployed state. A satisfactory deployable space reflector must also be easily and reliably deployable. A reflector for use in space must also be light in weight to meet the restrictions imposed by the propulsion means of present-day launch vehicles but when fully deployed it must have sufficient rigidity to prevent distortion of its reflective surface.

Although there are many uses for deployable reflectors in space and there have been numerous prior designs, many prior art reflectors have not satisfied all of the requirements of a satisfactory deployable reflector for use in space. Many deployable reflectors are not capable of presenting a sufficiently large reflective surface area or are not readily col lapsed into a compact launch package. Some reflectors are not readily deployable to form a rigid reflector structure with an undistortable reflective surface and do not possess sufficient strength in relation to their weight.

It is an object of this invention to provide a deployable reflector assembly that is capable of having a large reflective surface area.

Another object of this invention is to provide a deployable reflector assembly that is capable of being collapsed into a compact configuration.

Another object of this invention is to provide a deployable reflector assembly that is capable of presenting a rigid reflective surface that is not subject to distortion when the reflector is fully deployed.

A further object of this invention is to provide a deployable reflector assembly that is light in weight.

A further object of this invention is to provide a deployable reflector assembly that is easily deployed.

The present invention provides a deployable reflector assembly for electromagnetic radiation. The deployable reflector assembly comprises a deployable circular T-shaped reflector ring structure that surrounds and is attached to a deployable reflector and means for deploying the deployable circular T-shaped reflector ring structure.

In order that the invention may be more clearly set forth and better understood, reference is made to the accompanying drawings in which:

FIG. I is a perspective view of the deployable reflector assembly of this invention in its collapsed configuration;

FIG. 2 is a perspective view of the deployable reflector assembly of this invention in its partially deployed state;

FIG. 3 is a perspective view of the deployable reflector as sembly of this invention in its fully deployed state;

FIG. 4 is a cross section of the deployable circular T-shaped reflector ring of this invention taken along the line 6-4 of FIG. 3;

FIG. 5 is an enlarged broken perspective view of part of the structure shown in FIG. 11 showing reflector ring connecting means; and

FIG. 6 is an enlarged broken perspective view of part of the structure shown in FIG. I showing alternate reflector ring connecting means.

Referring first to FIGS. 1 through 3, there is shown the collapsible and deployable reflector assembly 10 that includes a deployable circular T-shaped reflector ring structure Ill that comprises a series of deployable panels that surround and are operatively connected to a deployable reflector 12.. The deployable circular T-shaped reflector ring structure 11 has folding panels 13 that are flexibly connected to each other at their outer edges by hinges l4 and are flexibly connected to each other at their inner edges by hinges 15 to permit the panels to fold together to form a compact ring when the deployable reflector assembly is in its collapsed configuration. Rotatable panels 116 are rotatably connected to the folding panels 13 by means of connecting rods, such as the L-shaped connecting rod 17 or the T-shaped connecting rod I8, that fit into the hinges I4 that connect the folding panels and into the hinges 119 located on the rotatable panel's surface. Rotatable panels 16 are flexibly connected to each other by means of the flat, wedge-shaped members 20 and hinges 21. The outer periphery of the deployable reflector 12 is connected to the inside of the folding panels 13 at the location indicated by reference numerals 2.2 (see FIGS. 2 and 3), so that this connection lies substantially in the plane of the rotatable panels I6 when the reflector ring structure 11 is fully deployed.

FIG. I illustrates the deployable reflector assembly 10 in its collapsed state. In the collapsed statev the folding panels 13 are folded together to form a compact ring with the deployable reflector 12 located in its center. In. the collapsed configuration, the rotatable panels 16 are located in a substantially vertical position and the entire deployable reflector assembly 10 forms a compact package that is capable of fitting within a small volume such as exists in a space launching vehicle of comparatively small diameter.

FIG. 2 illustrates the deployable reflector assembly 10 undergoing deployment. In FIG. 2, the folding panels I3 have begun to unfold and move outward causing deployment of the deployable reflector 12. As the folding panels 113 move outward the rotatable panels 116 begin to rotate about the connecting rods 17 and I8. This rotation of the rotatable panels 116 causes the flat, wedge-shaped members 20 located on the lower side of the reflector ring structure II to move in an upward direction and the flat, wedge-shaped members 20 located on the upper side of the reflector ring structure to move in a downward direction. This results in the rotatable panels l6 and the wedge-shaped members 20 tending to move into a common plane.

As illustrated in FIG. 2, deployment of the reflector as sembly I0 can be accomplished by deploying means operatively connected to the series of deployable panels of the ring structure Ill such as a wire 23 connected to the electric motor 24 or by the torsion springs 25. In order to provide for deployment by the electric motor 24, a wire .23 is threaded through eyelets 26 that are located on the folding panels 13 at a point that is substantially midway between the paired hinges I5 and through the eyelets 27 located on inner corners of the wedgeshaped members 20. The ends of the wire 23 are then connected to the electric motor 24. Deployment is then accomplished by starting the electric motor which reels in the wire 23 and causes it to tighten. Since the wire 23 is threaded through the eyelets 26 and the eyelets 27, the tightening of the wire 23 pulls the folding panels 13 outward and pulls the wedge-shaped members 20 into a common plane and this results in deployment. Torsion springs 25 located at the outer junction of the folding panels l3 can also be used to effect deployment of the reflector assembly Ill. These torsional springs 25 cause deployment of the reflector assembly 10 by exerting an outward opening force upon the folding panels 13. Either the wire 23 and the electric motor 24, or the torsion springs 25 can be used to maintain the reflector assembly I0 in its deployed condition after deployment.

The fully deployed collapsible reflector assembly III is illustrated in FIG. 3 and it can be seen that the folding panels 13 that comprise what will be termed a first deployable array of panels that are interconnected have moved outward to form substantially open cylindrical ring. The rotatable panels 16 have also rotated through almost an arc of from their collapsed positions, and they now lie in a common plane with the flat, wedge shaped members 20. The rotatable panels I6 and the wedge-shaped panels 20 comprise what will be termed a second deployable array of panels that are interconnected to from a substantially flat ring upon being deployed. This ring lies in a plane that is roughly or substantially perpendicular to the central axis of the cylinder formed by the fully deployed first array comprising the folding panels 13. The resulting deployed reflector ring structure 11 has a T-shaped cross section that is illustrated in FIG. 4 and this gives the deployed reflector assembly a high degree of rigidity from a lowweight structure.

FIGS. 5 and 6 are enlarged broken perspective views of part of the structure shown in FIG. 1 and shown in greater detail two means of connecting the rotatable panels 16 of the second deployable array of panels to the folding panels 13. In FIG. 5, the L-shaped connecting rod 17 is shown with its leg 28 pivotally joining the hinge segments 29 and 30 of the hinge 14 that is connected to the folding panels 13. The long shaft 31 of the L-shaped connecting rod 17 is rotatably mounted to the hinge 19 so as to permit the rotatable panel 16 to rotate. In FIG. 6 the T-shaped connecting rod 18 is shown with its short shaft 32 pivotally connecting the hinge segments 29 and 30 of the hinge 14 and the other short shaft 33 pivotally connecting the hinge segments 29 and 30 of another hinge 14. The long shaft 34 of the T-shaped connecting rod 18 is rotatably mounted to the hinge 19 so as to permit the rotatable panel 16 to rotate.

The folding panels 13, rotatable panels 16 and the wedgeshaped members that form the reflector ring structure 11 can be made from honeycomb sheets that are made from aluminum or a lightweight plastic or from fiberglass. Alternately, a truss type of structure can be used to form the components of the reflector ring structure 11. Other types of construction that can be utilized will be obvious to those skilled in the art.

The types of deployable reflectors 12 that can be used with the deployable T-shaped reflector ring structure 11 include various types of flexible reflective sheets such as strong plastic film that is aluminized on one or both of its sides. The plastic films that are suitable include films from a material known as Mylar or polyethylene terephthalate which is a polymer formed by the condensation reaction between ethylene glycol and terephthalic acid. Other types of reflectors that are satisfactory include flexible sheets in the form of a screen formed from intermeshed metal wires that are woven to provide a suitable open mesh construction or a fabric coated or plated with metal. Suitable fabrics include those made from Dacron which is a trademark for a synthetic polyester fiber made from methyl terephthalate and ethylene glycol. If a flat reflector is desired, these plastic films, metal screens or metallized fabrics must generally be designed so that they are stretched tight to form a flat reflective surface when the deployable circular T-shaped reflector ring structure 11 is fully deployed. If a dish or parabolic reflector is desired, then suitable structural elements or guy wires (not shown) that are familiar to those skilled in the art must be connected to the plastic film, the metal screen, or the metallized fabric so that upon deployment of the deployable circular T reflector ring the reflector will have the desired dish or parabolic configuration. An inflatable type reflector that consists of an airtight balloon having a metallized reflective surface can also be used with the deployable T-shaped reflector ring structure 11. In-

flation of the the balloon can take place as the reflector ring structure 11 is being deployed or after it has been deployed. Generally, the type of structure that should be used to form the reflector 12 will be dictated by the mission that the reflector is to accomplish and the type of radiation that is to be reflected.

Although the invention has been described in considerable detail with reference to certain preferred embodiments, it will be understood that variations and modifications may be made within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A deployable reflector assembly comprising a deployable reflector, a series of deployable panels surrounding and operatively connected to said deployable reflector, said series of deployable panels comprising a first deployable array of panels interconnected to form substantially an open cylinder upon deployment and a second deployable array of panels operatively connected to said first deployable array of panels, said second array of panels being inte;connected to form a substantially flat ring upon being deployed that lies in a plane that is substantially perpendicular to the central axis of said cylinder formed by said deployed first array of panels and deploying means operatively connected to said series of deployable panels for deploying said series of deployable panels.

2. The deployable reflector assembly of claim 1 wherein said series of deployable panels have a substantially T-shaped cross section upon being deployed.

3. The deployable reflector assembly of claim 1 wherein-the panels of said first array of deployable panels are flexibly connected at their edges to the adjacent panels of said first array of deployable panels to permit said panels to fold together to form a compact ring when the deployable reflector assembly is in its collapsed configuration.

4. The deployable reflector assembly of claim 1 wherein said second array of panels includes panels that are adapted to rotate and including connecting means operatively connected to said first array of panels and to a plurality of said rotatable panels of said second deployable array for rotatably connecting said plurality of rotatably panels of said second deployable array of panels to said first array of panels.

5. The deployable reflector assembly of claim 4 wherein said connecting means comprises substantially T-shaped connecting rods.

6. The deployable reflector assembly of claim 6 wherein said connecting means comprises substantially L-shaped connecting rods.

7. The deployable reflector assembly of claim 1 wherein said reflector comprises a flexible reflective sheet.

8. The deployable reflector assembly of claim 1 wherein said deploying means comprises torsion springs.

9. The deployable reflector assembly of claim 1 wherein said deploying means comprises a wire and means for tightening said wire.

10. The deployable reflector assembly of claim 9 wherein said tightening means comprises a motor. 

1. A deployable reflector assembly comprising a deployable reflector, a series of deployable panels surrounding and operatively connected to said deployable reflector, said series of deployable panels comprising a first deployable array of panels interconnected to form substantially an open cylinder upon deployment and a second deployable array of panels operatively connected to said first deployable array of panels, said second array of panels being interconnected to form a substantially flat ring upon being deployed that lies in a plane that is substantially perpendicular to the central axis of said cylinder formed by said deployed first array of panels and deploying means operatively connected to said series of deployable panels for deploying said series of deployable panels.
 2. The deployable reflector assembly of claim 1 wherein said series of deployable panels have a substantially T-shaped cross section upon being deployed.
 3. The deployable reflector assembly of claim 1 wherein the panels of said first array of deployable panels are flexibly connected at their edges to the adjacent panels of said first array of deployable panels to permit said panels to fold together to form a compact ring when the deployable reflector assembly is in its collapsed configuration.
 4. The deployable reflector assembly of claim 1 wherein said second array of panels includes panels that are adapted to rotate and including connecting means operatively connected to said first array of panels and to a plurality of said rotatable panels of said second deployable array for rotatably connecting said plurality of rotatably panels of said second deployable array of panels to said first array of panels.
 5. The deployable reflector assembly of claim 4 wherein said connecting means comprises substantially T-shaped connecting rods.
 6. The deployable reflector assembly of claim 6 wherein said connecting means comprises substantially L-shaped connecting rods.
 7. The deployable reflector assembly of claim 1 wherein said reflector comprises a flexible reflective sheet.
 8. The deployable reflector assembly of claim 1 wherein said deploying means comprises torsion springs.
 9. The deployable reflector assembly of claim 1 wherein said deploying means comprises a wire and means for tightening said wire.
 10. The deployable reflector assembly of claim 9 wherein said tightening means comprises a motor. 